Reaction Steps
Following the procedure as described in EXAMPLE 9 and making non-critical variations using 5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one to replace 3-methylspiro[furo[3,2-f][1,2]benzisoxazole-5,3′-indol]-2′(1H)-one, and 5-chloromethyl-2-oxazolidinone to replace 2-(bromomethyl)-5-(trifluoromethyl)furan, 1′-[(2-oxo-1,3-oxazolidin-5-yl)methyl]-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1H)-one was obtained (32%) as a colorless solid: mp 197-198° C.; 1H NMR (300 MHz, DMSO-d6) δ7.58 (s, 1H), 7.37-7.29 (m, 1H), 7.26-7.20 (m, 1H), 7.19-7.13 (m, 1H), 7.09-7.01 (m, 1H), 6.49-6.39 (m, 2H), 4.98-4.75 (m, 2H), 4.74-4.66 (m, 1H), 4.54-4.45 (m, 2H), 4.15-3.84 (m, 2H), 3.67-3.56 (m, 1H), 3.31-3.23 (m, 1H), 3.02-2.90 (m, 2H); 13C NMR (75 MHz, DMSO-d6) δ177.9, 177.6, 161.2, 160.6, 160.5, 158.3, 142.6 (2C), 132.2, 132.0, 128.7, 128.6, 123.5, 123.4, 123.0, 120.6, 120.5, 119.9, 119.0, 118.9, 109.7, 109.6, 92.5, 92.4, 79.8, 73.3, 73.2, 72.1, 56.8, 43.1, 42.7, 42.6, 28.4; MS (ES+) m/z 379.3 (M+1).
